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Types of WPDES Permits

Permitted Discharges

Industrial wastewater discharge

The DNR administers 38 major industrial permits issued primarily to paper mills and steam electric facilities. Major industrial permits are issued for industries with significant wastewater volumes which can impact the receiving water. Majors are determined by calculating an EPA score, which considers factors such as wastewater volume or stream flow, public health impacts, water quality and more.

All other specific (individual) industrial permits are considered industrial minors. Minor industrial permits span a variety of industrial activities including dairy, food processing, metal finishing, meat processing and manufacturing plants. Many of the facilities have both surface water and groundwater discharges regulated by the same permit. Besides being classified as major or minor, industrial permits are also determined to be complex and non-complex. Complex permits are those surface water discharges with water quality based effluent limits, categorical limits (the industry has wastewater which fits in an industrial category identified in NR 221-297, Wis. Adm. Code, and land disposal systems with groundwater monitoring wells. Industrial non-complex permits include discharges of low strength wastewater (which may or may not be treated) from small industries discharging to surface water with categorical limits.

The department also has the authority under s. 283.31(6), Wis. Stats., to regulate water intake structures for industrial facilities to meet the requirements of Section 316(b) of the federal Clean Water Act. More information is available on regulating intake structures under the WPDES permit program.

Municipal wastewater discharge

Since passage of the 1972 Federal Clean Water Act, Wisconsin communities invested a tremendous amount of time, labor and money to upgrade and construct wastewater treatment facilities for water quality improvements. As communities upgrade treatment facilities, some find combining systems into a joint regional treatment facility more economical. Other municipalities upgrade the existing facility or construct a new one at or near the existing site.

Publicly owned wastewater treatment plants that have a design flow of one million gallons per day or greater are considered majors, which applies to 86 of the municipal wastewater treatment plants in Wisconsin. Publicly owned wastewater treatment plants that have a design average flow of less than one million gallons per day are minors.

Pretreatment program

The DNR's Pretreatment Program is a requirement of the federal Clean Water Act law outlined in the Code of Federal Regulations (CFR) 40., in various sections and subsections. The term "pretreatment discharger" refers to the situation where the facility does not discharge their wastewater directly to the waters of the state. Instead, the discharge flows into a municipal sewage treatment plant (also called a POTW or publicly owned treatment works) and mixes with other sewage for treatment before it is discharged to the waters of the state. The U.S. EPA has designated the Wisconsin DNR to administer this federal code within the state. In response to this designation, the state has adopted several administrative codes that describe the requirements for pretreatment discharges. These are contained in chapters NR 211 and NR 220-297, Wis. Adm. Code.

Pretreatment dischargers are issued permits if regulated by publicly owned treatment works (POTWs) delegated to implement the program, or they are issued control documents if regulated by the department. Control documents can be issued directly to the facility by the DNR, or the DNR can pass this permitting authority on to the local POTW if the POTW is designated as a "control authority" for this function. Permits issued by control authorities have an expiration date; control documents issued by the DNR do not have expiration dates. A control authority can develop its own discharge requirements under its municipal ordinances, but they cannot be less restrictive than the federal regulations. The discharge limitations are grouped by categories of industrial and commercial dischargers and subgrouped by the federal standard industrial coding or SIC code that applies to that facility.

General wastewater discharge

The WPDES general wastewater discharge permits cover groups of facilities or industries with similar types of wastewater discharges to surface waters and/or groundwater.

Following issuance of a general permit, the department may grant or confer coverage, without further public notification, to any facility or operation at any time during the permit term, provided the facility or operation meets the applicability requirements of the general permit. Compliance with limitations contained in the permit must be attained at the time coverage is granted. If a facility is not meeting those terms and conditions, then coverage under the general permit cannot be granted or continued and a discharge may not occur until an individual permit is issued.

Once coverage under a general permit has been granted, compliance with the terms and conditions must be maintained or the department may take an enforcement action under the provisions of s. 283.89, Wis. Stats., for permit violations. The department may revoke general permit coverage for a discharger and issue an individual permit following the conditions in NR 205.08.

To obtain initial coverage under a general permit a discharger must contact the department by completing and submitting a “Request for Coverage” form. Please see general discharge permits for permit documents, request for coverage forms and other information on each of the industrial and municipal wastewater general permits.

Storm water discharge

To meet the requirements of Section 402 of the federal Clean Water Act, the DNR has developed a state storm water runoff permit program under ch. NR 216, Wis. Adm. Code. There are three categories of discharges to be regulated by WPDES storm water permits: industrial, municipal and construction site erosion control.

Animal waste discharge

Permits for Concentrated Animal Feeding Operations (CAFOs) are regulated through the Watershed Management Program.